1. Field of the Invention
The invention relates, in general, to treatment of ocular disease, and, in particular, to systems and methods for excitation of photoreactive compounds in eye tissue.
2. Description of the Related Art
Diseased cells may be killed by triggering a class of photoreactive compounds or photosensitizers with specific illumination wavelengths. Photosensitizers are used in photodynamic therapy (PDT) through light sources such as lasers to treat targeted eye tissue in a number of eye disease conditions. For example, in age related macular degeneration (AMD), glaucoma, and diabetic retinopathy (DR), photosensitizers may be used to inhibit formation or retard disease progression such as commonly indicated by sub-retinal fluid concentration, or rapidly uncontrolled vascular growth within diseased eye tissue. As an example, diseased eye tissue 10 can occur on a rear portion 12 of an eye 14, as shown in FIG. 1. The diseased eye tissue 10 would be a candidate for being targeted eye tissue in PDT.
Retardation or termination of uncontrolled vessel growth provides promise of extended visual function. Conventional approaches to PDT are challenged by requirements of light exposure of desired intensities, duration, shape, and timing when photosensitizers are present in the diseased tissue. Unfortunately, inaccurately generated illumination, such as misdirected or misshaped illumination, could cause photosensitizers to kill healthy eye tissue.